Epidemiologic study of gonococcal infections is hampered by the inaccessability of simple techniques that will subgroup clinical isolates of Neisseria gonorrhoeae. Acrylamide gel electrophoresis of cell proteins has been used to subgroup Mycoplasma, L-forms, Enterobacteracae, atypical Mycobacteria, Yersinia pestis, and various M types of Group A streptococci. The purpose of our study is to identify subgroups of gonococci by means of acrylamide gel electrophoresis patterns of their solubilized cell proteins. Gonococci grown on solid media are lyphilized followed by heat-extraction in buffer containing sodium dodecyl sulfate and 2-mercaptoethanol. The proteins contained in the extract are then separated by means of acrylamide gel electrophoresis. The resulting protein electrophoresis pattern is used to compare one gonococcal isolate to another. The electrophoresis patterns do not appear to be changed by serial subculture of the isolate. Colony types of a single isolate may have different eletrophoresis patterns. Identical electrophoresis patterns have been found with isolates cultured from sexual partners and isolates from patients with treatment failures. Work is continuing to see if the electrophoresis patterns are distinct enough to reliably subgroup N. gonorrhoeae. BIBLIOGRAPHIC REFERENCES: Noble, R.C., and B.B. Penny. Characterization of the Antibody Response to Type 12-M Protein of the Group A Streptococcus. Journal of Laboratory and Clinical Medicine 86:713-721, 1975. Noble, R.C., and B.B. Penny. Comparison of Leukocyte Count and Function in Smoking and Nonsmoking Young Men. Infection and Immunity. 12:550-555, 1975.